This invention relates to a rotation angle detecting device for forming a signal which varies in response to the angle of rotation of a rotating object.
Heretofore, in order to form a sinusoidal signal corresponding to the rotation of a rotating object, a rotary type variable resistor having a resistance pattern in the form of a sine wave and having its slider coupled to the rotating object has been utilized. With the rotary type variable resistor, the resistance value is varied in the form of a sine wave with the rotation of the rotating object.
However, this means is disadvantageous in that it is difficult to manufacture the resistance pattern for the variable resistor, and the variable resistor is low in durability.